1. Field of the Invention
The present invention relates to a steam generating method with an overall process of producing gas mixtures ready for enhanced oil recovery (EOR). In particular, the present invention relates to a direct contact steam generator with a fluid bed at a bottom of the generator vessel.
2. Description of Related Art Including Information Disclosed Under 37 CFR 1.97 and 37 CFR 1.98.
The fluid bed contains inorganic particle waste resulting from evaporated water or from used solid fuel. The fluid bed does not contain a fuel component, and solids are continually removed from the fluid bed as dry waste. There is no combustion in the fluid bed, but rather above the fluid, where the fuel and oxygen-rich gas are mixed.
There are patents issued in the field of the present invention. U.S. Pat. No. 4,377,066 issued to Dickinson on Mar. 22, 1983 describes a process for the combustion of slurry fuels in an up-flow pressurized fluidized bed. The water supplied with the fuel and the oxidizing gas are further condensed through a series of indirect heat exchangers and used to scrub the combustion solids. The solids are removed from the water. The combustion is done in a typical fluidized bed method where the pressurized oxidizer (air) is injected from below the fluidized bed fuel particles to support combustion. The combustion reaction is carried while the fuel is in the fluidized bed. The present invention includes a cold fluidized bed that does not include the carbonic fuel or support the combustion reaction. The fluid bed of the present invention, will support, solidify and eventually remove the solid particles from the supplied water and to some extent from the fuel. The method eliminates the need for a quenching bath and allows a pure ZLD (Zero Liquid Discharge) system.
U.S. Pat. No. 5,967,098 issued to Tanca et al. on Oct. 19, 1999 describes a process for fluid bed combustion of fuels, like oil shale in an up-flow atmospheric fluidized bed. Most of the combustion energy is recovered in the form of steam generated in boiler heat exchangers (non-direct steam generation) where there is no mixture of the low pressure flue gas with the steam. In one embodiment, only a portion of the energy is recovered to produce steam in an indirect heat exchanger at the bottom of down-flow combustor where the cold fluid bed is at the bottom of the pressurized vessel and most of the energy is used to generate the steam in a direct contact heat exchange while mixing the liquid water with the combustion gas. In the Tanca invention, all the water used for generating the steam (in the boiler heat exchangers) is treated clean BFW (Boiler Feed Water). The up-flow fluid bed of the Tanca patent is used to support the fuel and oxidizer mixer and combustion. The present invention includes a cold fluidized bed that does not include the carbonic fuel or support the combustion reaction.